It's believed that VISA is more popular. Most of the small bisinesses accept VISA because it charges 3% of transaction fee.
AMEX is the least popular credit card in Canada (from a business's perspective). It charges the most (6%).
It is also reported that 55% of Canadians pay off teir credit card bill in full each month.
So the rate is not the biggest concern if you're going to pay the bill in full. The anual fee is the concern at some extent.
A gold card may give you addtional benefit like rental car insurance. So a no fee gold card is a good option.